Development and Validation of Korean Aviation Turbulence Guidance (KTG) System

Korean aviation turbulence guidance (KTG) system has been developed using the Unified Model-based regional data assimilation and prediction system (RDAPS) of the Korea Meteorological Administration (KMA) and pilot reports (PIREPs) observed in East Asia. It is operationally forecasting mid- (10000-25000 ft) and upper-level (25000-40000 ft) turbulence four times (00, 06, 12, and 18 UTC) daily at the Korean Aviation Meteorological Agency (KAMA) since 06 UTC 19 Jan 2012. Performance of the KTG system in the recent four years (2011.6-2015.5) against the observed turbulence encounters reported from PIREPs and air flight data is evaluated in the present study. The skill score is represented by area-under-curve (AUC) in the probability of detection (POD) method using the null and moderate-or-greater (MOG) turbulence encounters. The operational-KTG predicts the observed turbulence events well, and its skill score is larger than 0.82 averaged over the four years. The performance increases significantly after March 2012, except in summertime, and it is likely due to better performance of RDAPS in the upper troposphere. The seasonal-KTG system, which considered differences in turbulence generation in each season separately, predicts turbulence slightly better than the operational-KTG. Although KTG is developed using PIREPs, its performance against turbulence estimated from flight data is as good as or even better than that against PIREPs. Forecasting results of the KTG system against recently reported two moderate and severe turbulence cases encountered in China and Japan, respectively, will be presented in the conference, along with some issues on improvement of aviation turbulence forecasting system.